RU2063929C1 - Method of porous granulated ammonium nitrate production - Google Patents

Abstract

FIELD: production of porous granulated ammonium nitrate. SUBSTANCE: porous granulated ammonium nitrate is produced by introduction into concentrated fusion of the latter first of trivalent iron sulfate as its water solution with sulfate concentration of 0.06 - 0.08 mass % in terms of Fe+++ . Then dispersant is introduced in mixture with water suspension bearing chalk. Produced granules are not cake, are water-resistant and have strength of 700 g/granule. EFFECT: improved process. 2 cl, 1 tbl

Description

 The invention relates to a technology for the production of inorganic substances used in the manufacture of explosive materials.

 The closest in technical essence and the achieved result is a method for producing porous granular ammonium nitrate by introducing into the alloy an aqueous solution of an NF dispersant (USSR author's certificate N 421627, class C О1 С 1/18, С О5 С 1/02, 1974) .

 However, the granules of ammonium nitrate obtained by this method have low strength and a high degree of caking, which does not allow transportation of this product in bulk.

 The invention provides a method for producing porous granular ammonium nitrate containing pore-forming additives and ferric sulfate by neutralizing ammonia with nitric acid, evaporation, introducing additives and granulation.

 The objective of the invention is to improve the quality of porous granular ammonium nitrate, including increasing the strength and water resistance of granules, reducing caking of the product.

 The result is achieved by adding an additive containing ferric sulfate to a concentrated alloy of ammonium nitrate, and then introducing a suspension consisting of pore-forming additives of chalk and NF dispersant. The granules obtained are treated with a mixture of fatty acids and paraffin.

A method of obtaining a porous granular ammonium nitrate with the proposed sequence of introducing additives into the concentrated melt of ammonium nitrate provides an increase in the strength and water resistance of granules due to the presence of Fe ⁺⁺⁺ ion. Ferric sulfate with excess acidity partially interacts with chalk to form calcium sulfate, which also increases the strength of the granules, and the carbon dioxide released as a result of the reaction increases the porosity of the amcelite granules.

The mechanism of interaction of pore-forming additives is described by the equation
Fe ₂ (SO ₄ ) 3 + 3CaCO ₃ + 6HNO ₃ 3СаSО ₄ + 2Fе (NO ₃ ) ₃ + 3CO ₂ + 3H ₂ O
In addition, part of ferric sulfate reacts with fatty acids, forming on the surface of the granules a film of iron salts of fatty acids, which increase the water resistance of the granules.

The addition of ferric sulfate with excess acidity up to 0.5 wt. introduced into the alloy amcelitra in the form of a solution at the rate of 0.06 0.08 wt. (in terms of Fe ⁺⁺⁺ ).

 The additive pore-forming component contains a certain amount of dispersant NF and chalk (ratio T: W = 1: 1) and is introduced in an amount of 0.2-0.5 wt.

After the introduction of ferric sulfate and pore-forming additives (chalk and dispersant NF), the process is carried out according to the usual scheme, i.e. the melt is granulated, then the granules are treated with a mixture of fatty acids and paraffin in an amount of 0.3
The porous granular ammonium nitrate obtained according to the method of the invention is practically non-caking, which makes it possible to transport this product in bulk.

 The product has improved physical and mechanical characteristics: the absorbency of granules 22-25 g / 100g; granule strength 650 - 750 g / gran. absorption capacity of 6-11 g / 100g of amcelite; water resistance 19-22 mm.

Example. In a concentrated melt of ammonium nitrate, an addition of ferric sulfate in the amount of 0.06 0.08 wt. then pore-forming aqueous suspension in an amount of 0.3 to 0.6 wt. After granulation, the obtained granules are treated with a mixture of paraffin and fatty acids. Examples of implementation are summarized in table
As can be seen from the table, the resulting product has an average absorption capacity of 8.3 g / 100 g of amcelitra, and an absorbent capacity of an average of 20.5 g / 100 g of amcelitra. The introduction of ferric sulfate in amcelitre melt increases the strength of the granules to 750 g / granule and completely eliminates its caking.

 The introduction of a smaller amount of iron sulfate (0.05 wt.) In amcelitra alloy somewhat reduces the strength of the granules and increases their caking ability (Example 1).

 An increase in the amount of iron sulfate (0.09) does not lead to an improvement in the physicomechanical properties of the product.

 With the introduction of an additive of an aqueous solution of a dispersant NF with chalk before a solution of iron sulfate, the main characteristics of the product decrease (example 7).

 With the simultaneous introduction of iron sulfate and an aqueous solution of the dispersant NF with chalk, the necessary absorbing and absorption capacity of porous ammonium nitrate is not achieved (example 8).

 In this regard, the introduction of ferric iron in large quantities, as well as after the introduction of the addition of the dispersant NF with chalk, is impractical due to a decrease in the quality of the product and an increase in its consumption. TTT1

Claims (2)

 1. A method of obtaining a porous granular ammonium nitrate, comprising introducing into the melt of ammonium nitrate an aqueous dispersant of NF with subsequent granulation of the obtained product, characterized in that ferric sulfate is preliminarily introduced into the concentrated melt, then the NF dispersant in a mixture with an aqueous suspension containing chalk. 2. The method according to claim 1, characterized in that the addition of ferric sulfate is introduced into the melt in the form of its aqueous solution with an iron sulfate content of 0.06 0.08 wt. in terms of Fe ⁺⁺⁺ .

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